Electrical measuring instrument.



G. WILER.

ELECTRICAL MEASURING INSTRUMENT. APPLICATION FILED SEPT. 10, 1906.

91 5,257. Patented Mar. 16, 1909.

3 SHEETS-SHEET 1.

jizaerafait' 'G. WILER.

ELECTRICAL MEASURING INSTRUMENT.

APPLICATION FILED SEPT.10, 1906.

9 1 5 ,257 Patented Mar. 16, 1909.

3 SHEETSSHEET 2.

G. WILER.

ELECTRICAL MEASURING INSTRUMENT.

APPLICATION FILED SEPT. 10,1906.

Z My mm W W 5 shipment.

UNITED STATES PATENT OFFICE.

CARL WILE R, OF CHICAGO, ILLINOIS, ASSIGNOR TO WESTERN ELECTRIC COMPANY,01

I CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

ELECTRICAL MEASURING INSTRUMENT.

Specification of Letters lPatent. Application filed September 10, 1906.Serial No. 334,024,

' Patented March 16, 1909.

To all whom it may concern: Be it known that I, CARL VViLnn, a citizenof the United States, residing at Chicago, in the county of Cook andState of Illinois, have invented a certain new and useful Improvement inElectrical Measuring Instruments, of which the following is a full,clear, concise, and exact description.

My invention relates toelectrical measur ing-instruments, and has forits object to provide an improved instrument which may be placedindiscriminately in alternating and direct current circuits withoutrecalibration, and which will be very accuratein its readings. Onefeature of myinvention consists in the manner of suspensionandfastening'of the coil and its armature, so as todecrease to a minimumthe friction of the moving parts,

and increase the efficiency of .the instrument.

I use a stationary solenoid coil, and pivot the armature or magneticvane below the coil before the lower opening thereof. I preferablyemploy a flat solenoid coil so as to bring the active turns thereof asclose as possible to the o armature. The vane or armature has axes ofunequal length, and normally presents its long axis to the coil. When,however, the vane is attracted and drawnwithin the coil, it presents itsshorter axis to the lines of force of the coil. With this arrangement,the

hysteresis efiects in the armature or vane'are reduced to a minimum andthe instrument rendered very accurate.

Another feature of. my invention consists in the provision of aremovable ,frame within the case adapted to support the indicatorneedle, pivoted vane and the dash pot. With thls arrangement the airchamber cannot be displaced with respect to its piston, and the frameand its supported parts may be removed from the case as a umt. T

A further feature of my invention consists in the provision of means forholding the indicating needle against vibrations .during To this end Iprovide a cam adapted to engage an arm within the case to cause the sameto hold the needle firmly its zero position.

I will describe my invention more particudrawings, which illustrate thepreferred embodiment thereof, and wherein Figure 1 is a verticalsectional view of a measuring instrument embodying my invention; Fig. 2is ;a front elevation showing the larly by reference to theaccompanying.

casing-in section; .Fig; 3 is a detail pel'spective view of the cam forlocking the needle; 'Fig. 4 is'a view of the removable unit; Fig. 5 is'aerspective view of the removable frame, and ig. 6 is a detailperspective view of the piston hereafter referred to.

The same letters of reference designate. the same parts wherever theyare shown.

The coil a of the instrument is rigidly mounted below the indicator cardor scale I), said coil being composed of a flattened Wire forming a flatsolenoid coil of little impedance. Below the coil is pivoted a magnetic,vane or armature 0 adapted to be drawn within the lower opening a ofthe coil to inove an indicator'needle d over the scale I). By reason ofthe location of the vane belowl the coil the friction of the movingparts opening, sot at the pivotal point of the,

.needle may be located in the central line of the instrument. The vanehas axes of un equal Length, andis elliptical in form. Said vane-iseccentrically pivoted, being preferr' ably mounted upon a shaft 0pivoted in j eweledbearings in the frame e, said shaft being preferablyof hosphor bronze so as to reduce the self-anduction of the instrument,and increase its efiioiency. The shaft 0 also carries the indicatorneedle (1. The vane c normally presents its 'long axis to the coil andwhen attracted by current in the coil, is rocked onits pivot and drawnwithin the coilopening a, moving the indicator needle over e scale, andpresenting a shorter axis to the lines offorce of the coil, thusreducingthe hysteresis effects to a minimum. Actual tests, carefullyconducted, have shown that such result follows from the arrangement.

her.

being supported by the frame e. The dash pot comprises an arc-shaped airchamber f aving a slot f z in its upper concave wall in which anextension or arm (1 from the needle (1 is adapted to move, said armpreferably extending downwardly from the pivotal point of the needle andbeing connected with the piston f moving within the chamber, said slotserving as an air ventfor the cham- The dash pot thus serves as a damperupon the needle (I, rendering the same dead-beat. The frame e, whichsupports the needle, vane and 'dash ot, is removably secured at e to thecase, an preferably comprises a main body portion e in the arms e ewhereof the shaft 0 is pivoted, said body portion having de ending armse to which the air chamber is secured. An exten sion 0*" of the bodyportion is secured to the frame of the case by screws e, or in anysuitable manner. With. this construction, the frame and its sup ortedparts may be conveniently removed as a unit from the case,

and Whenin place the air chamber is maintained in proper relation to itspiston. The air chamber f preferably comprises a body portion fstampedfrom a single piece of material, being open at its side, and providedwitha cover f adapted to fit u on said body portion. The iston fie preer-. ably an angular blade w ose sides engage the walls. of the chamber,and form a .Z-

--sha ed piston, said an ar sides preventi air om lealn'ng past t eblade or piston an so impairing the efficiency of the dash-pot.

In order to revent vibrations of the indicator needle uringshipmentfwhichmight injure the pivots of the moving parts, I-provide acam g adapted to be engaged by an arm h, to lock the needle in its zeroosition against vibration. The arm h, whic when. applied to a voltmeter,may serve as an index finger, is located between the needle and thefront wall of the case, and is adapted to be movedfrom the outside ofthe case by a button i, to ride up onto the cam which is also mountedupon the" front wa of the case. The arm it carries a finger h, which,when the arm rests uponsaid cam, is inter osed in the path of the needleand enga es t e same to lock it in its zero position. he cam g isprovided with an mclined portion 9 up which the arm ridesinto the-seatg, being.

' held against further movement in such direction by a sto I preferablgmake the front and sides of the casing of a single iece 7c of stampedsheet Ipreferab y make the piece 7: of iron. and secure a piece is ofsheet'iron to the rear metal.

wall k of the casing, so as to protect the coil 0, from stray fields.

I claim:

1. In an electrical measuring instrument, the combination with a flatsolenoid coil, of a magnetic vane having axes of unequal length,

pivoted/below said coil, and ada ted'to be rocked by current in saidcoil, sai vane normally presenting its long axis to said coil and whenrocked by current in said coil present ing a shorter-axis thereto,.andan indicato moving with said vane.

2. In an electrical measurm an elliptical ma net vane or armatureeccentrically pivote below said. coil, before the lower opening thereof,and an indicator operated by the movement of said vane.

the combination with a solenoid coil, of a magnetic vane having axes ofunequal length,

eccentrically pivoted below said coil before the lower opening thereof,said vane normally presenting its long axis to the coil, and when drawnwithin the coil by current in said coil, presenting a shorter axisthereto, and an in dicator needle operated by said :vane when rocked.

4. In an electrical measuring instrument,

the combination with a fiat solenoid coil, ofa

rocking shaft below the coil, 'an elliptical and an indicator needlepivoted upon said shaft. I

- 5. In an electrical measuring mstrument, the combination with acasing, of a solenoid .coil, a magnetic-vane responsive to current insaid coil, an indicator needle ,moved by said vane, a dash pot forrendering said needle dead-beat, and aframe removably secured withinsaid casing and supporting said needle, vane and dash-pot.

6. In an electrical measuring instrument, the combination with a casing,of a solenoid. coil, a magnetic vane pivotally supported before theopening of said coil, an in "cator needle moving with said vane, anair-chamber, a Z-shaped piston within said chamber connected with saidneedle tomove therewith, and a frame removably secured within saidcasing and forming a mounting for said needle, vane, and air-chamber.

7. In a measuring instrument, the combination with the case thereof, ofan indicating needle therein, a cam upon the inner surface ofthe frontof said case, and an arim adaptedt'o be .operated from the outside ofthe case to engage said cam to lock said needle in its.

zero osition against vibration.

n a measuringinstrument, the combinatlonwlth the case thereof, of anindicating needle therein, a cam upon the inner surface of the front ofsaid case, an arm between said needle and the front of the case, adaptedto v be rocked from the outside ofthe case, said instrument, thecombination with a flat so enoid coil, of

. 3. In an electrical measuring instrument,

arm being adapted when moved to ride up onto said cam, andan'angular-finger carried tion to lock the indicator needle against v1-bration, -and means for operating said arm from the outside of the case.

10. In an electrical measuring instrument, the combination with asolenoid coil, of a magnetic vane having axes of unequal length, saidvane being mounted in'position to be rocked by current in said coil,said vane g normally presenting its long axis to said coil,

and when rocked by current in said coil presenting a shorter axisthereto, and an indicator moving with said vane.

11. In an electrical measuring instrument, the combination with asolenoid coil, of an elliptical magnetic vane or armatureeccentricallypivoted before an o enin of said coil, and an indicatoroperate by t ment, of said coil,

12. In an electrical measuiing instrument, the combination with asolenoid coil, of a magnetic vane having axes of unequal lengtheccentrically pivoted before an opening of" said coil, said vanenormally presenting its long. axis to the coil, and when drawn withinthe coil by current in said coil presenting a shorter axis thereto, andan indicator needle.

operated by said vane when rocked.

13. In an electrical measuring instrument,

the combination with a solenoidcoil, of a rocking shaft mounted acrossthe opening of said coil, an elliptical magnetic vane having 7 unequalaxes eccentrically pivoted'on said 6 moveshaft at approximately acentral position with respect to the opening of said coil, said vanenormally resenting its longest axis to said coil and w on attracted androcked by current in said coil presenting ashorter axis to the lines offorce of the coil, and an indicator needle pivoted upon said shaft.

In witness whereof, I, hereunto subscribe my name this 28th day ofAugust A. D., 1906.

CARL WILER.

Witnesses o C. A. CoGGIN, GEORGE P. BARTON.

